I need to prevent users from selecting a different tab in TabView. The solution using onChange no longer works on iOS 18.

Steps to reproduce:

1. Navigate from Home → Details → (UI works as expected)
2. Navigate from Home → Directory (blocked by onChange) → Details (UI breaks)
3. Navigate from Home → Directory (blocked by onChange) → Details (UI breaks) -> Back (Now we can't navigate to Details anymore).

struct TabViewBugView: View {
  enum AppTab {
    case home
    case directory
  }
  
  @State private var selection: AppTab = .home
  
  var body: some View {
    TabView(selection: $selection) {
      NavigationStack {
        NavigationLink {
          VStack {
            Text("Details")
            Spacer()
          }
        } label: {
          Text("Go to Details")
        }
        
        Text("HomeView")
      }
      .tabItem {
        Label("Home", systemImage: "house")
      }
      .tag(AppTab.home)
      
      
      Text("Directory")
        .tabItem {
          Label("Directory", systemImage: "folder")
        }
        .tag(AppTab.directory)
    }
    .onChange(of: selection) { oldValue, newValue in
      print("\(oldValue) -> \(newValue)")
      if newValue == .directory {
        selection = oldValue
      }
    }
  }
}

How can I properly prevent tab selection without breaking the UI?

I need to prevent users from selecting a different tab in TabView. The solution using onChange no longer works on iOS 18.

Steps to reproduce:

1. Navigate from Home → Details → (UI works as expected)
2. Navigate from Home → Directory (blocked by onChange) → Details (UI breaks)
3. Navigate from Home → Directory (blocked by onChange) → Details (UI breaks) -> Back (Now we can't navigate to Details anymore).

struct TabViewBugView: View {
  enum AppTab {
    case home
    case directory
  }
  
  @State private var selection: AppTab = .home
  
  var body: some View {
    TabView(selection: $selection) {
      NavigationStack {
        NavigationLink {
          VStack {
            Text("Details")
            Spacer()
          }
        } label: {
          Text("Go to Details")
        }
        
        Text("HomeView")
      }
      .tabItem {
        Label("Home", systemImage: "house")
      }
      .tag(AppTab.home)
      
      
      Text("Directory")
        .tabItem {
          Label("Directory", systemImage: "folder")
        }
        .tag(AppTab.directory)
    }
    .onChange(of: selection) { oldValue, newValue in
      print("\(oldValue) -> \(newValue)")
      if newValue == .directory {
        selection = oldValue
      }
    }
  }
}

How can I properly prevent tab selection without breaking the UI?

• swiftui
• navigation
• onchange
• block
• tabview

• A custom tab bar would be one way to fix, then you can disable any buttons that are supposed to be, well, disabled. See this answer for an example implementation. – Benzy Neez Commented 52 mins ago
• Btw, Apple's Human Interface Guidelines discourage this type of behaviour: Don’t disable or hide tab bar buttons, even when their content is unavailable. Having tab bar buttons available in some cases but not others makes your app’s interface appear unstable and unpredictable. If a section is empty, explain why its content is unavailable. – Benzy Neez Commented 47 mins ago

1 Answer 1

cool. this code veru nice, relli nice